The use of multiple output converters having a primary and secondary of a power transformer utilizing choke filters for each output is well known. The choke filter is usually an inductor used as in low pass filter in which the useful output is a direct current. In power converters it is used as a filter of a power rectifier in a secondary to filter out resulting superimposed ripples. At the usual power frequencies, the filter choke may have an iron core, with an air gap to minimize variations of inductance with the direct current. As shown in FIGS. 1 and 2, a multi-output pulse width modulated (PWM) power supply is shown utilizing choke filtering on the secondary of the power transformer. This is a typical four transistor PWM whereby the output is controlled by switching the transistors on and off by control circuitry to maintain an appropriate output. Each output requires the rectifying of a diode steering bridge along with the filtering by a choke filter and a capacitor to smooth out the resulting pulsating current. In a power supply with many outputs or in a case of high voltage output, the choke filters involved may be too bulky for high density packaging which finds ever increasing applications.
Because of this, the use of systems requiring choke filtering on the output of the secondary have been somewhat limited in their application especially in airborne equipment. And accordingly there exists a need for a multi-output PWM power converter that can be utilized in high density packaging while insuring effective operation of the system.